LONDON, Dec 27 With grass underfoot and darkness enveloping Centre Court, Rafael Nadal took over from Roger Federer as the world's best tennis player in 2008.

The clay-court king finally made his breakthrough on a fast surface, following up his four straight French Open titles with a victory at Wimbledon - ending Federer's five-year winning streak at the All England Club.

“Is impossible to explain what I felt in that moment,” Nadal said after the 6-4, 6-4, 6-7 (5), 6-7 (8), 9-7 win. “I am very happy for me but sorry for him, because he deserved this title, too.”

A day after winning the Olympic gold medal in Beijing, Nadal officially became the world's top-ranked player, taking over a position Federer had held for a record 237 weeks. Federer finished the season as No 2, only 10 points ahead of third-ranked Novak Djokovic, who won the Australian Open after beating the Swiss star in the semi-finals.

By his high standards, Federer had his worst season since starting his streak at the top in 2004, even though he reached three of the four major finals.

He overcame a bout of mononucleosis early in the year and lost to Nadal in the French Open final for the third straight season before winning the US Open for his 13th Grand Slam title, but he still only won four events in 2008 - one by forfeit. That total, however, doesn't include his doubles gold medal from the Beijing Olympics.

“It has been a tough season with lots of travelling and I could just sleep for a month,” said Federer, who needs one more major title to equal Pete Sampras' record of 14.

The women's game saw several changes at the top after the surprising retirement of then-25-year-old Justine Henin, who became the first player to quit the WTA Tour while ranked No 1.

After winning her fourth French Open and adding a second US Open title in 2007, Henin started the 2008 season poorly and made her announcement in May, only weeks before the start of the tournament at Roland Garros.

“I gave the sport all I could and took everything it could give me,” Henin said. “I take this decision without the least bit of regrets. It is my life as a woman that starts now.”

In the absence of Henin, Ana Ivanovic won her first major title, beating Dinara Safina in the French Open final. Ivanovic lost to Henin in the 2007 final.

At the All England Club, Venus Williams won her fifth Wimbledon title despite entering the tournament with a 14-7 record in 2008, beating younger sister Serena in the final.

“When I get here I feel like it's a different ball game, no matter what my results were, good or bad, in the beginning,” said Venus, who won her seventh Grand Slam title. “This is Wimbledon. No matter what, I'm going to play good here. That's really how I felt about it.”

Serena wasn't completely outdone, however. She won her ninth major title at the US Open, beating Jelena Jankovic in the final.

Maria Sharapova, who won the Australian Open, was the first player to take over the No 1 ranking after the retirement of Henin. Since then, Serena Williams, Jankovic and Ivanovic took turns at No 1, with Jankovic finishing the season at the top.

Although Sharapova missed much of the year because of a shoulder injury, Russia still went on to win its second straight Fed Cup title, and its fourth in five years. Also without Olympic singles champion Elena Dementieva, Russia beat Spain 4-0 in the final.

Spain won the Davis Cup title, however, even without the injured Nadal. Feliciano Lopez and Fernando Verdasco won singles matches to help Spain defeat host Argentina 3-1.

“It's the most exciting victory of my life,” Verdasco stated. “Playing for my country, against the best players, it's a dream.”

Off the court, fifth-ranked Nikolay Davydenko was cleared by the ATP in September after a yearlong investigation into suspicious betting patterns on a match he lost in 2007. Several other players were punished for bet

ting violations in 2008.

At Wimbledon, Nadal upset the odds.

After losing to Federer in the previous two Wimbledon finals, Nadal entered the 2008 tournament playing just about as well as ever, cutting through the opening rounds and losing just one set in the process. Federer, predictably, lost none, and was only pushed to three tiebreakers in his first six matches in his attempt to equal Willie Renshaw's record six straight Wimbledon titles.

But Nadal had the better start in the final - after a 35-minute rain delay - winning the first two sets. More rain came in the third set, but Federer still managed to rebound by taking the next two sets in tiebreakers, saving some match points along the way.

At 2-2 in the fifth, play was stopped again, this time for about 30 minutes. Action resumed at 823pm, and both players held serve through 7-7 as darkness descended.

Nadal then managed the first break of the match since the second set, and followed that by holding serve to win one of the greatest tennis matches ever played and end Federer's 40-match winning streak at Wimbledon.

“It's rough on me now,” Federer said after that momentous defeat. “Obviously, you know, to lose the biggest tournament in the world over maybe a bit of light.”—AP